Between the first and fourth centuries A.D., Hopewell Indians built nine burial mounds near Sumnerville, and the six remaining earthen mounds reflect the Hopewellian culture that flourished in the Eastern Woodlands of North America, primarily in Illinois and Ohio. Sumnerville is one of the few places in Michigan where Hopewellian mounds survived into the twentieth century, preserved by landowners while most mounds were destroyed by plowing or construction. Some artifacts removed from the mounds in the late nineteenth century were acquired by the Public Museum of Grand Rapids, and archaeologists named Sumnerville Incised, a type of Hopewellian pottery, for its association with this site. Sumnerville Cemetery contains the earliest marked grave dating from 1830, bearing the name Emily Markham, and it holds many Pokagon pioneers, including the prominent African American families of Ash, Gault, Mitchem, and Mitchell. The cemetery also contains the remains of Cass County's first white settlers, Uzziel and Anna Putnam, who came to Pokagon Prairie in 1825, along with Charity Thompson, widow of Berrien County's first white settler, Squire Isaac Thompson, and two of their children. Veterans beginning with the War of 1812, as well as judges, legislators, and township officials, are interred there, and since 1990 Pokagon Township has cared for the cemetery.